Question

我在tblStudentDetails中有两个条目，RollNo = 0和1 但每当我尝试从数据库中检索数据时，我总是得到第一条记录，即RollNo = 0 这是我的代码：

<?php

    unset($_SESSION['RollNo']);
    unset($_SESSION['StudentName']);
    unset($_SESSION['Course']);

    include_once 'Includes/DBConnection.php';

    //echo $_POST['txtRollNo'];

    if ($_POST['btnSubmit'] == 'Submit')
        {
           if ($_POST['txtRollNo'] != '')
               {
                   $query = "SELECT StudentName, Course FROM tblStudentDetails WHERE RollNo = '$_POST[txtRollNo]'";
                   $result = mysql_query($query);

                   $rowCount = mysql_num_rows($result);

                   if ($rowCount == 0)
                       { 
                           echo "You have entered an incorrect roll No";
                           //header ('Location: index.php');
                       }
                   else
                       {
                           while ($row = mysql_fetch_assoc($result))
                               {
                                   $StudentName = $row['StudentName'];
                                   $Course = $row['Course'];
                               }

                           $_SESSION['RollNo'] = $_POST['txtRollNo'];
                           $_SESSION['StudentName'] = $StudentName;
                           $_SESSION['Course'] = $Course;

                           header ('Location: SelectedUserDetails.php');
                       }
               }
           else
               {
                    echo "Please Enter Your Roll No.";
                    //header ('Location: index.php');
               }
        }
?>

<html>
    <head>
        <title>Online Exam</title>
        <STYLE TYPE = "Text/CSS">
            H1
                {
                    Color : DodgerBlue;
                    Text-Align : Center
                }
            HR
                {
                    Color : DodgerBlue
                }
            LABEL
                {
                    Vertical-Align : Bottom;
                    Font-Size : 20
                }
            TR
                {
                    Height : 30;
                    Background : White;
                    Color : Black;
                    Font-Size : 20
                }
        </STYLE>
   </head>

    <BODY BGCOLOR = "BLACK" TEXT = "WHITE">
        <CENTER>
            <TABLE ALIGN = "CENTER">
                <TR>
                    <?php include 'Includes/header.html'; ?>
                </TR>
                <TR>
                    <TD>
                        <TABLE>
                            <TR>
                                <FORM NAME = "frmMain" METHOD = "POST" ACTION = "<?php echo $PHP_SELF ?>" enctype = "multipart/form-data">
                                    <TD>
                                        Enter your roll no. : 
                                    </TD>
                                    <TD>
                                        <INPUT TYPE = "TEXT" NAME = "txtRollNo" />
                                    </TD>
                                    <TD>
                                        <INPUT TYPE = "SUBMIT" NAME = "btnSubmit" VALUE = "Submit" />
                                    </TD>
                                </FORM>
                            </TR>
                        </TABLE>
                    </TD>
                </TR>
            </TABLE>        
        </CENTER>
    </BODY>
</html>

在SelectedUserPage中，我尝试检查$_SESSION['RollNo']的值，但它始终为null。谁能说出上面代码中的问题是什么？

Answer 1

您尚未使用session_start()开始会话。

无法在php中从数据库中正确检索数据

1 个答案: